The multi-wavelength and multi-messenger view of Active Galactic Nuclei

Neutrinos travel nearly unattenuated over cosmological distances, making them an excellent messenger to study high-energy processes occurring in the universe. This was seen on 22 September 2017, when the IceCube neutrino observatory reported a high-energy neutrino event which was found to be coincident with a flaring blazar, TXS 0506+056, seen by the Fermi-LAT. However, a separate time-integrated study using IceCube data reported that a Seyfert galaxy, NGC 1068, is a source of astrophysical neutrinos. Because of the different nature of the two sources and the lack of significant neutrino and gamma-ray correlation, there exists confusion regarding the processes that lead to the production of these neutrinos in Active Galactic Nuclei (AGN). A way to tackle this is to perform correlation studies using multi-wavelength and multi-messenger data. This talk will describe a similar correlation study that uses both model-dependent and model-independent approaches to better understand the neutrino production mechanism in AGN. The data used in the study is collected using observations from NICER, NuSTAR, CHANDRA  and Fermi-LAT missions and neutrino data comes from IceCube. I will also briefly mention important future NASA missions that can help us better understand these open questions.

Bring your lunch to enjoy during the seminar.